Mercury speciation in brain tissue of polar bears (Ursus maritimus) from the Canadian Arctic

Krey, Anke; Kwan, Michael; Chan, Hing Man

doi:10.1016/j.envres.2012.01.006

Cited by 30 publications

(37 citation statements)

References 61 publications

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“…In this same brain region, MeHg comprised 83% of the THg present. Krey et al (2012) documented that brain MeHg comprised 100% of the brain total mercury in Canadian polar bears from Nunavik (Fig. 2).…”

Section: Mercury-selenium Relationships and Interactionsmentioning

confidence: 99%

What are the toxicological effects of mercury in Arctic biota?

Dietz

Sonne

Basu

et al. 2013

Science of The Total Environment

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► Unpublished and published data were compiled for Arctic fish, birds, and mammals. ► These data were compared to available toxicological threshold limits. ► Toothed whales, polar bears, and some bird and fish species exceeded the limits. ► Increasing mercury concentrations are observed for some Arctic species. ► These exceeded thresholds and increasing Hg trends are of concern. a b s t r a c t a r t i c l e i n f o This review critically evaluates the available mercury (Hg) data in Arctic marine biota and the Inuit population against toxicity threshold values. In particular marine top predators exhibit concentrations of mercury in their tissues and organs that are believed to exceed thresholds for biological effects. Species whose concentrations exceed threshold values include the polar bears (Ursus maritimus), beluga whale (Delphinapterus leucas), pilot whale (Globicephala melas), hooded seal (Cystophora cristata), a few seabird species, and landlocked Arctic char (Salvelinus alpinus). Toothed whales appear to be one of the most vulnerable groups, with high concentrations Science of the Total Environment 443 (2013) [775][776][777][778][779][780][781][782][783][784][785][786][787][788][789][790]

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Section: Mercury-selenium Relationships and Interactionsmentioning

confidence: 99%

What are the toxicological effects of mercury in Arctic biota?

Dietz

Sonne

Basu

et al. 2013

Science of The Total Environment

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321

202

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“…Field studies of behavioral effects of POPs in polar bears are, of natural causes, difficult to conduct. However, several POPs and methylmercury reported in brain tissue of polar bears, (Greaves et al, 2012(Greaves et al, , 2013Krey et al, 2012;Dietz et al, 2013a) are known or suspected developmental neurotoxicants in humans and experimental animals Landrigan, 2006, 2014;Fonnum and Mariussen, 2009;Mariussen, 2012).…”

Section: Combined Effects On Neurological Processes Behavior and Devmentioning

confidence: 99%

Anthropogenic flank attack on polar bears: interacting consequences of climate warming and pollutant exposure

et al. 2015

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Polar bears (Ursus maritimus) are subjected to several anthropogenic threats, climate warming and exposure to pollutants being two of these. For polar bears, one of the main effects of climate warming is limited access to prey, due to loss of their sea ice habitat. This will result in prolonged fasting periods and emaciation and condition related negative effects on survival and reproduction success. Prolonged fasting will result in increases of the tissue concentrations of persistent organic pollutants (POPs) in polar bears, and thus increase the probability for POP levels to exceed threshold levels for effects on health, and thus on reproductive success and survival. There are clear potentials for interactions between impacts of climate warming and impacts of pollutant exposure on polar bears. It is likely that that fasting-induced increases of POPs will add to mortality rates and decrease reproductive success beyond effects caused by loss of habitat alone. However, there is a lack of studies that have addressed this. Thus, there is a need to focus on population effects of POP exposure in polar bears, and to consider such effects in relation to the effects of climate induced habitat loss.

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“…The chemical forms of Hg were analyzed via high-performance liquid chromatography (HPLC; Agilent 1200 series HPLC system, Agilent Technologies Canada Inc., Mississauga, ON, Canada), equipped with autosampler, quaternary pump, and 100 mL injection loop. A ZORBAX Eclipse XDB-C18 Column (2.1 mm × 50 mm, 5 μm) was connected to an inductively coupled mass spectrometer (ICP-MS; Agilent Technologies™, 7500 CX), following extraction using a method developed by Krey et al (2012). Each sample batch (n = 33) included one blank and DOLT-4 (dogfish liver, NRC; triplicate) to ensure quality within and between batches.…”

Section: Sample Collectionmentioning

confidence: 99%

Biomarkers of the cholinergic and dopaminergic signaling pathways in Arctic beluga whales (Delphinapterus leucas): relationship to methylmercury and selenium

Ostertag

Chan

2018

Arctic Science

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There are increasing concerns about potential neurotoxicity of chronic methylmercury (MeHg) exposure in Arctic wildlife and human populations. The relationships between mercury (Hg), MeHg, inorganic Hg (iHg), and selenium (Se) exposure, and neurochemical and molecular biomarkers in beluga whales (Delphinapterus leucas (Pallas, 1776)) were characterized. Samples were collected in 2008 (n = 20) and 2010 (n = 15) in the Canadian Arctic from hunter-harvested beluga whales. Total Hg concentrations in the temporal cortex and cerebellum were 21.0 ± 22.6 mg kg −1 dry weight (dw) and 14.9 ± 18.9 mg kg −1 dw, respectively. Monoamine oxidase (MAO) activity was predicted by MeHg and the molar ratio of total Hg to Se (Hg:Se, p < 0.05); MAO-A mRNA transcription levels were predicted by iHg and Se (p < 0.05). Muscarinic AChR binding was predicted by MeHg (p < 0.05) and Hg:Se molar ratio (p < 0.05), and mRNA transcription levels of mAChR m1 was predicted by the Hg:Se molar ratio (p < 0.05). These results suggest that the cholinergic and dopaminergic signaling pathway in Eastern Beaufort Sea beluga whales may be sensitive to MeHg exposure. The response of beluga whales to MeHg exposure at a physiological and population level remains to be elucidated.

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Mercury speciation in brain tissue of polar bears (Ursus maritimus) from the Canadian Arctic

Cited by 30 publications

References 61 publications

What are the toxicological effects of mercury in Arctic biota?

What are the toxicological effects of mercury in Arctic biota?

Anthropogenic flank attack on polar bears: interacting consequences of climate warming and pollutant exposure

Biomarkers of the cholinergic and dopaminergic signaling pathways in Arctic beluga whales (Delphinapterus leucas): relationship to methylmercury and selenium

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